Rotary engine



No. 6l0,|9l. Patented Sept. 6, I898.

c. J. MILLIGAN.

ROTARY ENGINE.

lication filed Sept. 18, 1897 CHARLES J. MILLIGAN, or CHICAGO, ILLINOIS.

ROTARYENGINE.

SPECIFIGATION forming part of Letters Ifatent No. 610,191, dated September 6, 1898. Application filed September 13, 1397. Serial noiesinaz. (No model.)

To aZZ whom it may concern:

Be it knownthat I, CHARLES J. MILLIGAN, a citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, have invented certain new and useful,

Improvements in Rotary Engines; and I do declare the following to be a full, clear, and exupon the known constructions of this type of engine, so as to secure a balance of pres sure upon adjacent heads, thereby relieving the mechanism of strain and preventing back pressure thereupon, and to provide for the shifting of the movable bulkheads by means of a steam-cushion developed between the advancing piston and the bulkhead which has been last in service. Its further object is to provide improved means for regulating the steam-service to'the engine. These ob jects are secured in the construction hereinafter fully described and illustrated in the drawings, in which-,-

Figure 1 is an end elevation of the engine,

showing the automatic cut-off. Fig. 2 is an.

elevation of the opposite end, showing the gearing for controlling the bulkheads. Fig. 3 is a transverse vertical section through the body of the engine. Fig. 4 is a longitudinal section on the line 4 4 of Fig. 3. Fig. 5 is a detail section of the service-pipe and cut-off valve. Figs. 6 and 7 show a detail of the bulkhead-gearing.

The body A of the engine is in drum or cylindrical form, its interior being dressed to afford a circumferential bearing-surface concentric with its axis and also lateralbearingsurfaces. The body portion is provided, pref-f erably. at the top, with an extension: at, simi-. larlyinternally finished, its internal circum-' ferential line, however, passing into the chamber of the body portion.

The drive-shaft B of the engine is j ournaled on the axis of the body portion and carries an annulus O of such width that its side edges have a bearing upon the inner surfaces of the end walls of the bodyportion, the diameter of the annulus, however, being sufficiently less than the internal diameter of the body to provide an annularexpansion-chamber X,

:within which the piston moves.

The annulus G is secured to the shaftB by means of the hub c, and the piston-blade D is secured to and projects radially from its periphery, the areaof the piston being equal to the cross-section of the chamber X, so that it has bearings upon the side and circumferential wallsof the body portionA.

A shaft F is journaled upon the axisof the extension o of the body portion and carries a hub G, from which radiate six bladesg, so as to form a star-wheel, these blades bearing upon the side wallsof the extension at and also against its inner circumferential face.

The parts are so disposed that the outer ends of the blades 9 impinge against the face of the annulus C as they pass it, thereby completely crossing the expansion-chamber X, and the piston-blade D intermeshes with the blades 9 as it revolves. When one of the blades 9 is in contact with the annulus O, the

two adjacent blades coincide with the angles of the juncture of the body portion A with the extension a, and the faces of the blades are concave, so that when their tips are at these angles their faces forma continuation of the inner face of the circumferential wall of the body portion. The rearward face continues this curve nearly to the hub G, being then interrupted to form a suitable recess for the apex of the piston-blade D. The forward faces of the blades recede from this line of curvaturefrom a pointconsiderably nearer the tip of the blade, so as to permit the starwheel to begin its forwardmovement before the piston-blade has reached the blade of the star-wheel which is about. to be displaced from the expansion-chamber. These'blades g are successively brought and, by means herein after described, held in position exactly transverse to the expansion-chamber that is to say, upon a line passing through the centers of movement of the piston and the starwheeland thereby form bulkheads against which the steam admitted back of the pistonblade reacts.

The induction-port M is located immediately in front of the blade g which is serving as the bulkhead, and the cut-off valve, hereinafter described, for controlling the steam-service is timed in its movement, so that steam begins to enter when the piston is practically in contact with the bulkhead, and hence there is no clearance-space which must be filled with live steam before pressure is developed upon the piston-blade. This action is made possible by so shaping the rearward faces of theblades that the one which has last been in service as abulkhead and designated g in the drawings forms a continuation of the peripheral wall of the expansion-chamber substantially to the then acting bulkhead, (designated g.)

The exhaust-port O is located back of the bulkhead ashort distance and in the side wall of the expansion-chamber and is at all times open save while the piston is passing it. A by-pass 0 is formed in one of the walls of the expansion-chamber in radial alinement with the port 0 and has sufficient circumferential length, so that when the port 0 is closed by the piston steam will pass through the bypass to the forward side of the piston. As soon as the piston has left the by-pass 0 the steam which has passed it forms a cushion, and the pressure thus developed tends to move the star-wheel. The portO is so located that the cushion is developed as the piston moves over the face of the blade of the starwheel which is next to be brought into service as a bulkhead, and when the piston passes the concave portion of the face of this blade the star-wheel begins to move and the blade remains in contact with the piston and closes down behind it, the steam-cushion being relieved as soon as the bulkhead, being the blade marked 9, passes out of contact with the face of the annulus O.

The service of steam to the port M is through the pipe m, within which the cut-off valve P is located. This cut-off valve is actuated by an eccentric P, mounted upon the shaft B and connected with the valve by means of a rod 19 and a crank-arm p, fixed to the valvestem. The rod 13 is in two sections united by a turnbuckle 19 whereby the position of the valve in the casing may be adjusted so that the steam will be cut off at such point in the revolution of the piston as may be desired.

The star wheel carrying the bulkheadblades is controlled by means of a collar-cam Q, mounted upon the shaft B and intermeshing with a crown-wheel 7c, fixed upon a shaft h, journaled in bracket-hangers h, secured to one of the end walls of the body portion A of the engine, a bevel-gear H, fixed upon the upper end of the shaft h, intermeshing with a bevel-gear f, fixed upon the shaft F. The

teeth of the crown-gear 717 are shown as pins,

as 10 11 12 13, and in order that the cam Q may engage only one side of this gear the shaft his set somewhat inclined from the perpendicular. The cam Q is in the form of a flange lying in a plane exactly transverse to the shaft B through nearly three hundred and sixty degrees and then having a somewhat abrupt offset of as great extent as the distance between adjacent teeth of the crown-wheel, its final end portion being in a plane parallel with its major portion. The forward end of the cam therefore enters between two of the teeth of the crown-gear, as 11 and 12, before its rearward end passes out of engagement with the teeth 12 13. The crown-wheel is locked against rotation by the cam Q, except as it is engaged by the offset thereof, and hence steam-pressure upon the blade g cannot move the star-wheel.

When the engine is in the position shown in Fig. 3, steam is entering between the piston-blade D, as shown in solid lines, and the blade g immediately behind it. Until the piston-blade passes beyond the apex of the blade g with which its outer end'is in contact there is back pressure upon the blade g in excess of the forward pressure upon the blade 9 but when the entire face of the blade g is exposed to the pressure of the steam the forward pressure and the backward pressure are equalized and strain upon the cam Q is relieved.

The engine may be packed in any suitable manner. As shown, a packing is provided for the sides of the annulus 0 comprising rings E of any suitable material set in channels in the side walls of the body portion and held in contact with the annulus by screws 6, set through these side walls and bearing against it. By turning up these screws this packing may be set up more closely to compensate for wear.

The cam Q is so adjusted circumferentially upon the shaft B as to bring its offset or oblique portion into engagement with the crownwheel 70 just as the piston-blade reaches the end of the concave portion of the face of the blade of the star-wheel next to serve as a bulkhead, and the length of the oblique portion of the cam is such that its end is reached as the blade of the star-wheel reaches its position as a bulkhead.

I claim as my invention 7 1. In a concentric piston rotary engine the combination with the body portion and the piston, of a plurality of revolving bulkheads mounted togetherso as to successively cross the expansion-chamber,and being so disposed that when one bulkhead is transverse to the expansion-chamber adjacent bulkheads coincide with the inner peripheral face of the body portion, the rearward faces of the bulkheads being concave to correspond with the curvature of such face, and their forward faces receding toward their bases so that the bulkheads may begin to advance while the piston-blade is in contact with the face of the head next to cross the expansion-chamber, an induction-port entering the expansion-chamber immediately forward of a line through the centers of movement of the piston and the bulkheads, an exhaust-port back of and removed from such line and a by-pass in the wall of the body portion and in radial alinement with the exhaust-port.

2. In a rotary steam-engine, the combination with a casing having an annular pressure-chamber and a lateral chambered extension open to such pressure-chamber, of a piston-blade traveling in the pressure-chamber, a plurality of bulkheads radiating from a common hub journaled within the extension so that the heads successively cross the pressure-chamber, the inner Wall of the casing being provided with a bypass of greater circumferential length than the width of the piston, whereby steam may pass the piston.

3. In a rotary steam-engine, the combination with a circular casing having a lateral chambered extension, an annulus journaled concentrically within the casing and of less diameter than its chamber, a radiating piston-blade carried by the annulus and sweeping the walls of its casing, a plurality of bulkheads radiating from a common hub and journaled within the lateral extension of the casing so as to contact successively with the periphery of the annulus, an exhaust-port in the side wall of the casing outside of the annulus, a bypass formed in the inner wall of the casing in radial alinement with the exhaust-port and of greater length than the thickness of the piston-blade, whereby steam may pass the piston-blade for the purpose of advancing the bulkhead.

4. In a concentric piston rotary engine havinga plurality of rigidly-connected revolving bulkheads adapted to be successively brought to position across the expansion-chamber of the engine, of a bevel-pinion mounted on the shaft of such heads, a bevel-gear intermeshing with such pinion, a shaft carrying the bevel-gear, a crown-wheel mounted upon the shaft, a collar-cam mounted upon the engineshaft and intermeshing with the crown-wheel, such cam having oblique and straight portions whereby intermittent movement is communicated to the bulkheads and such heads are rigidly held between their successive steps.

5. In a concentric rotary engine the combination with the body portion having an annular expansion-chamber, a piston revolving in such chamber, a shaft carrying the piston, a plurality of rigidly-connected revolving bulkheads adapted to successively cross the expansion-chamber and being so disposed that the heads adjacent to the head immediately in service form continuations of the peripheral wall of the expansion-chamber, of an induction-port immediately forward of a line through the centers of movement of the piston and the bulkheads, an exhaust-port back of and removed from such line, a by-pass in the wall of the expansion-chamber and in radial alinement with the exhaust-port, a collarcam on the engine-shaft and having straight and oblique portions, a crown-wheel interpansion-chamber and being so disposed that the heads adjacent to the head immediately in service form continuations. of the peripheral wall of the expansion-chamber, of an induction-port immediately forward of a line through the centers of movement of the piston and the bulkheads, an exhaust-port back of and removed from such line, and a bypass in the wall of the expansion-chamber and. in radial alinement with the exhaust-port.

7 In a concentric rotary engine the combination with the body portion having an annular expansion-chamber, a piston revolving in such chamber, a shaft carrying the piston, a plurality of rigidly-connected revolving bulkheads adapted to successively cross the expansion-chamber and being so disposed that the heads adjacent to the head immediately in service form continuations of the peripheral wall of the expansion-chamber, of an induction-port immediately forward of a line through the centers of movement of the piston and the bulkheads, an exhaust-port back of and removed from such line, a by-pass in the wall of the expansion-chamber and in radial alinement with the exhaust-port, and means for positively holding the bulkhead in place until the piston-blade has passed the exhaust-port.

In testimony whereof I aflix my signature in presence of two witnesses.

CHARLES J. MILLIGAN. Witnesses:

' LOUIS K. GILLsoN,

SAKE D. THOMPSON. 

